A particular, though not exclusive, application of the invention is to writing on metallized paper. The formation of characters on metallized paper by selective erosion of the metallization has already been proposed. In British Specification No. 1,099,871 published Jan. 17, 1968 characters are formed by matrix printing techniques such as have been developed in relation to high speed printers used with electronic data processing equipment. To this end a sheet of metallized paper is moved transversely to and in contact with a set of electrodes disposed in line. By selective energisation of the electrodes the metallization is vaporized to form the required characters.
The present invention is concerned with making lines on a material by use of a writing implement, for example a stylus used in the manner of a pen. Thus the lines formed may be written to form alphanumeric characters and the like or in forming drawings, graphs and so on. In particular there has been a need in certain security applications to give hand-writing a distinctive characteristic by which it may be verified.